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How Vitamin B12 Can Boost Your Energy

If you’re deficient in the nutrient, getting more B12 may recharge your battery.

Fast Facts

  • Vitamin B12 is essential for energy. If you don’t get enough of it, you can feel fatigued, weak, and generally run down.
  • Eating B12-rich foods, oral supplements, and B12 injections can all raise your levels back to the normal range.

Plenty of supplements claim to boost energy and fight fatigue. Few deliver. But one actually might: vitamin B12. Low levels of the nutrient are linked with fatigue—so much so that some B12 deficient people report feeling like they’re dying. And some who supplement with it say they feel “born again.” Sounds pretty promising. But does vitamin B12 give you energy regardless of the cause? 

What is B12?

Also known as cobalamin, vitamin B12’s biggest claim to fame its role in blood cell formation and nervous system function. But B12 isn’t a one-trick nutrient: It also helps with DNA synthesis and the formation of brain and nerve cells (1).

Does Vitamin B12 Give You Energy?

There’s a direct link between vitamin B12 and energy. B12 helps your body convert fat and protein in order to provide energy to the body, says Peter Kozlowski, M.D., a functional medicine doctor in Chicago.

Your body also needs B12 to make red blood cells, which ferry oxygen to your tissues, a process that’s needed to feel strong and energized throughout the day.

B12 is also vital for your nervous system. It maintains myelin–a fatty nerve insulator that optimizes signaling from your brain–to make sure muscles contract when they’re needed (among other things).

If your B12 levels are low (a blood test can determine if your levels are in the right range) it can cause a myriad of symptoms that zap your physical and mental energy. Getting those levels back up through supplementing typically helps improve symptoms, says Kozlowski.

Anecdotally, people who aren’t B12 deficient report feeling hyped-up after B-12 injections. Some doctors are starting to listen: In one Swiss study (2), almost half of all general practitioners agreed with prescribing B-12 for unexplained fatigue.

Vitamin B12 at a Glance

  • Your body needs vitamin B12 to create red blood cells and DNA. Your nervous system also uses it to maintain myelin.
  • If you are B12 deficient, you may experience symptoms including fatigue, weakness, depression, and more. Supplementing with B12 often erases these symptoms.
  • Some people who aren’t B12 deficient report feeling energized after supplementing with the nutrient, although research hasn’t proven this benefit.

Signs of B12 Deficiency

About six percent of Americans under the age of 60—and 20 percent of those over 60—have a B12 deficiency (1). Not getting enough B12 doesn’t just make you feel devoid of energy; it can make you downright miserable. Symptoms of a deficiency include:

  • Weakness
  • Fatigue
  • Weight loss
  • Depression
  • Irregular heartbeat
  • Dizziness
  • Shortness of breath
  • Tingling in hands and feet

Since your body stores a lot of B12, a deficiency doesn’t happen overnight—it can take years to show up and cause these symptoms (3).

Causes of B12 Deficiency

Most people get enough B12 from their diet (3), but dig deeper and you’ll discover that you can chow down on enough B12-rich food and still be deficient. How’s that work? Some acid-blocking medications, such as PPIs (omeprazole, lansoprazole)—which are among the most-prescribed drugs in the U.S. (4)—can interfere with B12 absorption. The same goes for certain antacids (cimetidine), and the diabetes drug metformin.

Mental and emotional factors like stress, anxiety, and depression can also affect the release of stomach acid needed to digest protein (which ensures that B12 is released from your food), says Kozlowski.

Other people who might not get enough from their diet? Vegetarians and vegans, since the nutrient is mainly found in meat and dairy.

Medical conditions that can also put you at risk for a B12 deficiency include:

  • Pernicious anemia
  • Gastric surgery
  • Crohn’s disease
  • Celiac disease

Vitamin B12, now available from Hone, may boost your energy, reduce stress, and support your brain. Connect with a doctor to see if it’s right for you. 

Vitamin B12 Deficiency

  • Vitamin B12 deficiency can cause both physical and mental symptoms including fatigue, depression, dizziness, and weight loss.
  • Taking certain medications can put you at risk for a B12 deficiency. You’re also at risk if you don’t eat enough foods that are rich in B12.
  • Medical conditions, especially those that impact your body’s ability to absorb nutrients, can also increase your risk for a B12 deficiency.

How Does B12 Work?

B12 is bound to protein in meats and animal products (5). As these foods travel through your digestive system, your stomach releases hydrochloric acid and enzymes which set the B12 free. The unbound B12 then combines with another protein (called intrinsic factor, which is secreted by cells in the stomach) before it is absorbed by the body in the small intestine and put to work.

If you’re taking a supplement or eating fortified foods (such as breakfast cereal), your body can skip the first step of breaking them off from the protein, making absorption easier.

B12 is a water-soluble vitamin, so any excess you take in will be peed out.

Vitamin B12 in Your Diet

The National Institutes of Health recommends that the average man consume a mere 2.4 micrograms a day, which you can get by scarfing just three ounces of ground beef. Other B12-rich food options include:

  • Clams
  • Tuna
  • Salmon
  • Beef
  • Milk
  • Yogurt
  • Cheese
  • Egg
  • Poultry
  • Liver
  • Fortified nutritional yeast
  • Fortified breakfast cereals
  • Enriched soy or rice milk

B12 in Your Body

  • Your body can’t make B12. You need to get it from food or supplements.
  • When you eat B12-rich foods, your body releases enzymes that release it so your body can use it.
  • Most dietary B12 come from animal sources. Cereals and nutritional yeast are also often fortified with B12.

Get More B12

If a blood test determines that you’re clinically deficient (that’s lower than 200 picograms per milliliter (pg/mL), you can up your levels a few ways.


If you’re a meat-eater, leveling up your B12 could be as simple as making sure that you’re eating enough B12-rich foods every day, according to the Cleveland Clinic. (6)

Oral Supplements

Vegetarians, vegans, and people who suffer from medical conditions that makes it hard for the gut to absorb nutrients may need a supplement to boost their B12 levels and energy.

You can find B12 on its own, or in a supplement with other B vitamins and other nutrients. Supplements with a variety of B vitamins in them will have less B12 than a standalone B12 pill.

B12 deficiency often goes hand in hand with a folate deficiency, says Kozlowski. For that reason, your doctor may order a serum folate level when testing for B12. “Both vitamins are needed for DNA synthesis and your body will not function properly if both levels are not balanced,” he says. (Normal serum folate levels are above 3 ng/mL.) (7) If you’re low in both, B-complex vitamin might help. Talk to your doctor about the dose that’s right for you.


In instances where someone has lower levels of the nutrient, B12 injections can bring levels up faster, says Kozlowski. 

You can work with Hone to see if B12 injections are right for you. Simply create an account, then describe your symptoms using Hone’s online form. A board-certified physician will review your answers, and prescribe B12 shots if they feel they can help give you energy or help in other ways. If your prescription is approved, B12 injections will be sent straight to your door. 

B12 can be injected underneath the skin or into the muscle. You can get your B12 shot in a doctor’s office, but your doctor may also give you the okay to self-inject at home. 

The Bottom Line

If you don’t get enough B12, you can suffer symptoms like muscle weakness, fatigue, memory problems, dizziness, short breath, and heart palpitations. If a blood test confirms that your B12 levels are low, supplementing can get your levels of the nutrient back to normal and help you feel more energized. If your B12 levels are normal, there is no evidence that supplements will further boost your energy.